TESTING/EIG/ddrgvx.f(3)

NAME
TESTING/EIG/ddrgvx.f

SYNOPSIS

  Functions/Subroutines
subroutine ddrgvx (nsize, thresh, nin, nout, a, lda, b, ai, bi, alphar, alphai, beta, vl, vr, ilo, ihi, lscale, rscale, s, dtru, dif, diftru, work, lwork, iwork, liwork, result, bwork, info)
DDRGVX

Function/Subroutine Documentation

  subroutine ddrgvx (integer nsize, double precision thresh, integer nin, integer nout, double precision, dimension( lda, * ) a, integer lda, double precision, dimension( lda, * ) b, double precision, dimension( lda, * ) ai, double precision, dimension( lda, * ) bi, double precision, dimension( * ) alphar, double precision, dimension( * ) alphai, double precision, dimension( * ) beta, double precision, dimension( lda, * ) vl, double precision, dimension( lda, * ) vr, integer ilo, integer ihi, double precision, dimension( * ) lscale, double precision, dimension( * ) rscale, double precision, dimension( * ) s, double precision, dimension( * ) dtru, double precision, dimension( * ) dif, double precision, dimension( * ) diftru, double precision, dimension( * ) work, integer lwork, integer, dimension( * ) iwork, integer liwork, double precision, dimension( 4 ) result, logical, dimension( * ) bwork, integer info)

DDRGVX

Purpose:

    !>
    !> DDRGVX checks the nonsymmetric generalized eigenvalue problem
    !> expert driver DGGEVX.
    !>
    !> DGGEVX computes the generalized eigenvalues, (optionally) the left
    !> and/or right eigenvectors, (optionally) computes a balancing
    !> transformation to improve the conditioning, and (optionally)
    !> reciprocal condition numbers for the eigenvalues and eigenvectors.
    !>
    !> When DDRGVX is called with NSIZE > 0, two types of test matrix pairs
    !> are generated by the subroutine DLATM6 and test the driver DGGEVX.
    !> The test matrices have the known exact condition numbers for
    !> eigenvalues. For the condition numbers of the eigenvectors
    !> corresponding the first and last eigenvalues are also know
    !> ``exactly'' (see DLATM6).
    !>
    !> For each matrix pair, the following tests will be performed and
    !> compared with the threshold THRESH.
    !>
    !> (1) max over all left eigenvalue/-vector pairs (beta/alpha,l) of
    !>
    !>    | l**H * (beta A - alpha B) | / ( ulp max( |beta A|, |alpha B| ) )
    !>
    !>     where l**H is the conjugate transpose of l.
    !>
    !> (2) max over all right eigenvalue/-vector pairs (beta/alpha,r) of
    !>
    !>       | (beta A - alpha B) r | / ( ulp max( |beta A|, |alpha B| ) )
    !>
    !> (3) The condition number S(i) of eigenvalues computed by DGGEVX
    !>     differs less than a factor THRESH from the exact S(i) (see
    !>     DLATM6).
    !>
    !> (4) DIF(i) computed by DTGSNA differs less than a factor 10*THRESH
    !>     from the exact value (for the 1st and 5th vectors only).
    !>
    !> Test Matrices
    !> =============
    !>
    !> Two kinds of test matrix pairs
    !>
    !>          (A, B) = inverse(YH) * (Da, Db) * inverse(X)
    !>
    !> are used in the tests:
    !>
    !> 1: Da = 1+a   0    0    0    0    Db = 1   0   0   0   0
    !>          0   2+a   0    0    0         0   1   0   0   0
    !>          0    0   3+a   0    0         0   0   1   0   0
    !>          0    0    0   4+a   0         0   0   0   1   0
    !>          0    0    0    0   5+a ,      0   0   0   0   1 , and
    !>
    !> 2: Da =  1   -1    0    0    0    Db = 1   0   0   0   0
    !>          1    1    0    0    0         0   1   0   0   0
    !>          0    0    1    0    0         0   0   1   0   0
    !>          0    0    0   1+a  1+b        0   0   0   1   0
    !>          0    0    0  -1-b  1+a ,      0   0   0   0   1 .
    !>
    !> In both cases the same inverse(YH) and inverse(X) are used to compute
    !> (A, B), giving the exact eigenvectors to (A,B) as (YH, X):
    !>
    !> YH:  =  1    0   -y    y   -y    X =  1   0  -x  -x   x
    !>         0    1   -y    y   -y         0   1   x  -x  -x
    !>         0    0    1    0    0         0   0   1   0   0
    !>         0    0    0    1    0         0   0   0   1   0
    !>         0    0    0    0    1,        0   0   0   0   1 , where
    !>
    !> a, b, x and y will have all values independently of each other from
    !> { sqrt(sqrt(ULP)),  0.1,  1,  10,  1/sqrt(sqrt(ULP)) }.
    !>

Parameters
    NSIZE

    !>          NSIZE is INTEGER
    !>          The number of sizes of matrices to use.  NSIZE must be at
    !>          least zero. If it is zero, no randomly generated matrices
    !>          are tested, but any test matrices read from NIN will be
    !>          tested.
    !>

    THRESH

    !>          THRESH is DOUBLE PRECISION
    !>          A test will count as  if the , computed as
    !>          described above, exceeds THRESH.  Note that the error
    !>          is scaled to be O(1), so THRESH should be a reasonably
    !>          small multiple of 1, e.g., 10 or 100.  In particular,
    !>          it should not depend on the precision (single vs. double)
    !>          or the size of the matrix.  It must be at least zero.
    !>

    NIN

    !>          NIN is INTEGER
    !>          The FORTRAN unit number for reading in the data file of
    !>          problems to solve.
    !>

    NOUT

    !>          NOUT is INTEGER
    !>          The FORTRAN unit number for printing out error messages
    !>          (e.g., if a routine returns IINFO not equal to 0.)
    !>

    A

    !>          A is DOUBLE PRECISION array, dimension (LDA, NSIZE)
    !>          Used to hold the matrix whose eigenvalues are to be
    !>          computed.  On exit, A contains the last matrix actually used.
    !>

    LDA

    !>          LDA is INTEGER
    !>          The leading dimension of A, B, AI, BI, Ao, and Bo.
    !>          It must be at least 1 and at least NSIZE.
    !>

    B

    !>          B is DOUBLE PRECISION array, dimension (LDA, NSIZE)
    !>          Used to hold the matrix whose eigenvalues are to be
    !>          computed.  On exit, B contains the last matrix actually used.
    !>

    AI

    !>          AI is DOUBLE PRECISION array, dimension (LDA, NSIZE)
    !>          Copy of A, modified by DGGEVX.
    !>

    BI

    !>          BI is DOUBLE PRECISION array, dimension (LDA, NSIZE)
    !>          Copy of B, modified by DGGEVX.
    !>

    ALPHAR

    !>          ALPHAR is DOUBLE PRECISION array, dimension (NSIZE)
    !>

    ALPHAI

    !>          ALPHAI is DOUBLE PRECISION array, dimension (NSIZE)
    !>

    BETA

    !>          BETA is DOUBLE PRECISION array, dimension (NSIZE)
    !>
    !>          On exit, (ALPHAR + ALPHAI*i)/BETA are the eigenvalues.
    !>

    VL

    !>          VL is DOUBLE PRECISION array, dimension (LDA, NSIZE)
    !>          VL holds the left eigenvectors computed by DGGEVX.
    !>

    VR

    !>          VR is DOUBLE PRECISION array, dimension (LDA, NSIZE)
    !>          VR holds the right eigenvectors computed by DGGEVX.
    !>

    ILO

    !>              ILO is INTEGER
    !>

    IHI

    !>              IHI is INTEGER
    !>

    LSCALE

    !>              LSCALE is DOUBLE PRECISION array, dimension (N)
    !>

    RSCALE

    !>              RSCALE is DOUBLE PRECISION array, dimension (N)
    !>

    S

    !>              S is DOUBLE PRECISION array, dimension (N)
    !>

    DTRU

    !>              DTRU is DOUBLE PRECISION array, dimension (N)
    !>

    DIF

    !>              DIF is DOUBLE PRECISION array, dimension (N)
    !>

    DIFTRU

    !>              DIFTRU is DOUBLE PRECISION array, dimension (N)
    !>

    WORK

    !>          WORK is DOUBLE PRECISION array, dimension (LWORK)
    !>

    LWORK

    !>          LWORK is INTEGER
    !>          Leading dimension of WORK.  LWORK >= 2*N*N+12*N+16.
    !>

    IWORK

    !>          IWORK is INTEGER array, dimension (LIWORK)
    !>

    LIWORK

    !>          LIWORK is INTEGER
    !>          Leading dimension of IWORK.  Must be at least N+6.
    !>

    RESULT

    !>              RESULT is DOUBLE PRECISION array, dimension (4)
    !>

    BWORK

    !>          BWORK is LOGICAL array, dimension (N)
    !>

    INFO

    !>          INFO is INTEGER
    !>          = 0:  successful exit
    !>          < 0:  if INFO = -i, the i-th argument had an illegal value.
    !>          > 0:  A routine returned an error code.
    !>

Author
    Univ. of Tennessee

    Univ. of California Berkeley

    Univ. of Colorado Denver

    NAG Ltd.

Definition at line 296 of file ddrgvx.f.

Author

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